a) Field of the Invention
The present invention relates to apparatus and method for controlling drive of a three-phase multiplex winding motor and, more particularly, relates to vector control apparatus and method for the three-phase N-plex (N=2, 3, 4,- - -) winding motor preferably with a secondary resistance variation compensation method.
b) Description of the Related Art
Japanese Patent Application First Publications No. Showa 62-100191 published on May 9, 1987 and No. Showa 63-305792 published on Dec. 13, 1998 exemplify previously proposed drive systems for multiplex winding AC motors.
Each of these systems drives an N-plex winding motor through N number of inverters to permit a large capacity of the motor (N=2, 3, 4, - - -).
Each of the previously proposed drive systems for the N-plex winding motor through the correspondingly same phase voltage or current so as to drive the N-plex winding motor.
However, an object of providing each of the previously proposed drive systems is merely to achieve a larger capacity of the motor. In addition, a decoupling control cannot be achieved as has been carried out in a conventional three-phase induction motor.
Examples of literatures describing the decoupling controls for the three-phase induction motors are listed below.
Literature 1:
"Comparison of Practical Performances between Controlled Current Source and Controlled Voltage Source Vector Control Systems" described in a Japanese Paper of an institute of Electrical Engineering (J-IEE) D, volume 107 No. 2, published in 1987, and authored by Masayuki Terashima, et al.
Literature 2:
"Compensation for Parameters Variation of Induction Motor Improved Torque Control Characteristics at Low and High Speed Region" described in the Japanese Paper of the institute of Electrical Engineering (J-IEE) D, volume 112 No. 2, published in 1992, and authored by Tetsuo Yamada, et al.